Drafting machine rolling contact distance calculator



June 3, 1947. J, SCOTT 2,421,581

DRAFTING MACHINE ROLLING CONTACT DISTANCE CALCULATOR Filed June 13, 1945 2 Sheets-Sheet l 22 F g INVENTOR.

f0 HI @0011 BY} W ATTORAEY June 3, 1947.

J. H. SCOTT DRAFTING MACHINE ROLLING CONTACT DISTANCE CALCULATOR 2 3 4 5i lllllllllllll] l Ill'lILlllJllhlllLllJflllLLLhhh Filed June 13, 1945 2 Sheets-Sheet 2 INVENTOR.

JOHNH SCOTT sygmw ATTORNEY Patented June 3, 1947 TED aoFFic-I:

DRAFTINGMACHINE ROLLING CONTACT DI*STANCE CALCULATOR 1 J 01m =H. -Sctt,- Houston, Tex.

*A pplicationfJune 13, 1945, Serial'No. 599,136

1 This invention relates to drafting'machines, and aims to provide a d-rafting machine-calcu- -lator-adapted to register the distance that the drafting machine is moved on the drafting board, either vertically, horizontally, or diagonally. The calculator maybe constructed into-a drafting machine or it may-be constructed'separately and attached to the machine. The calculator may be so graduated that itenables the draftsman croperator to read instantly the distance 1 the 'machine has been moved, even down to very small-or minutedistances, thereby "eliminating the=need for other measuring means.

The above and other objects will become apparent in the description be1ow,-wherein characters of reference refer to like-numbered'partsin the accompanying' drawings. 'It is to be -noted that the drawings are intended-for the purpose'yof illustration only, and that it is neither-desired nor intended to limit the invention in any manner to the specific details of construction shown excepting insofar as they may be deemed essential to the invention.

Referring briefly to the drawings, Fig. 1 is a plan view of the calculator.

Fig. 2 is a cross-sectional view taken on the line 22 of Fig. 1.

Fig. 3 is an enlarged fragmentary and partly phantom or outline view of a drafting machine, showing the calculator mounted thereon.

Fig. 4 is a cross-sectional view taken on the line 44 of Fig. 2.

Referring in detail to the drawings, the numeral I0 indicates the upper and the numeral I I the lower of a pair of spaced parallel plates held together by posts I 2. A crank shaft I3 having the crank I4 forming part thereof, is rotatably mounted upright between the plates I0 and II and has its extremities p ojecting b d both plates. A staff I5 secured between the plates has one end of a spring I 5 anchored thereon, the other end of this spring being loosely secured to the crank I4. A somewhat conical, disc-like dial I1 is secured to the upper end of the shaft I3 and is provided with peripheral graduations I8; the upper plate I0 surrounding the dial I1 is likewise provided with graduations I9. Spaced collars on the shaft I 3 on either side of the lower plate I I permit of limited vertical movement of the shaft I3. A spring finger 2| secured against the plate II has its free extremity normally urged against the hub 22 of a horizontal bevel gear 23 fixed on the lower end of the shaft I3. A pin 24 slidably mounted in a barrel 25 supported under the plate ID on a radius of the shaft I3, is normally urged outwardfrom the barrel by a spring 26. The spring I6 obviously normally urges the shaft I3 into the position shown in" Figs. 1 and 2; in alignmentzwith the pin-24 and on the diametrically opposite side 'of the shaft (to thecrank I4) the shaft has a rounded'indentation or notch"2I, The end of the pin 24 is complementarily rounded and obviously normally registersqin thenotchz-l, thereby providing a readily releasable. friction-lock to maintain'the'shaft13in the sai'd'normal position. The 'graduations' on the dial II may be so marked as to indicate the'zero position or reading on the dial with the shaft I3 in the said normal position.

-*At"one side 'of'the'dial a pin "28 is slidably mounted in the plates "I-IJand II and-nearits lower endis-enlarge'd' to provide a bearing support 29 through which a shaft 30 rotatably extends. On one end of the shaft 3!! a bevel gear 3| -isfixed and is adapted tobe engaged, in the manner tobe-described, with thebevel gear'23. On the other end of the shaft 38 a friction or traction wheel 32 is fixed; the shaft extends beyond the wheel 32 and has a pinion 33 on its extremity. An upright wall or guide 34 is supported between the plates I0 and I I and is provided with a vertical slot 35 through which the pinioned end of the shaft 38 passes. A button 36 is provided on the upper extremity of the pin 28, and a coiled spring 31 normally urges the button, and hence the .pin 28, gear 3I and wheel 32 upward so that normally the gear 3| is out of engagement (not shown) with the gear 23 and the wheel 32 is raised above the board, not shown.

A stub shaft 38 is rotatably mounted in the wall 34 and has rigid intermediate its length thereon a graduated wheel 39 provided with internal annular teeth 40 in which the pinion 33 registers when the button 36 is in its depressed position shown in Fig. 2. The plate I0 is slotted at 4|, and through the slot the upper portion of the wheel 39 projects. The free end of the shaft 38 is deformed into a hook, and a coiled spring 42 secured to the plate I0 and to the hook 43 normally maintains the hook 43 upright. The zero graduation on the wheel 39 is so placed that in the said normal position of the wheel the zero graduation is indicated against the index arrow 44 on the plate adjacent the slot 4|.

In Fig. 3 one type of drafting machine is shown fragmentarily, and it comprises the base member 45 having the articulated arms 41 and 48 extending therefrom, the latter being pivoted to the support 49. The two straight edges 50 and 5| extend from the member 46 at right angles thereto. The calculator, shown at 45, is illustrated mounted in and forming part of the member-46'.

It is apparent that when the vertical distance that the machine, or the member 46, is moved on the drawing board is to be measured, the machine is moved along that distance with the button 36 depressed to engage bevel gear 3| with bevel gear 23 and to engage simultaneously pinion 33 with gear teeth 40 of the wheel 39. Frictional engagement of the wheel 32 against the board, or paper, will cause, during movement of the machine, rotation of the shaft l3 and of the dial ll, and'with proper graduations on the dial and the plate Ill surrounding the same the distance may be readily measured thereon. For measurement of the distance moved in a horizontal direction, the mechanism described is identically repeated in a position at right angles to that described, shown at :52, excepting for the staff [5, spring l6, and crank shaft l3 and its directly associated parts including the dial ll, since all of these are common to both calculator mechanisms, and the vertical bevel gears of both are positioned movably above the horizontal bevel gear 2 3 ready for engagement therewith selectively. Therefore similar parts of the mechanism '52 are indicated by the same reference numeral followed by the letter a. Fine readings may be had on the dial l1, and coarser readings on the wheel 39, as is obvious. The spring 2| serves as a shock absorber to prevent straining or missing of the mechanism when passing over uneven or rough places on the paper or board. To measure distances of diagonal movement of the machine, the latter may be swung into position until either of the calculator wheels 32 or 32a is in line with the movement.

I claim:

a pair of spaced plates having means for securing the plates together in spaced parallel relationship, a crank shaft vertically rotatably mounted between said plates and having its extremities projecting through the plates, the upper extremity of said shaft having a dial thereon, the lower extremity of said shaft having a horizontal bevel gear thereon, a pin slidably projecting through said plates and having an enlarged portion between the plates, said portion having a horizontal shaft extending rotatably therethrough, said horizontal shaft having a vertical bevel gear on one end thereof positioned above said horizontal gear and adapted to be engaged therewith, the other end of said horizontal shaft having a friction wheel rigid thereon of greater diameter than said vertical bevel gear, resilient means normally urging said pin upward to maintain said vertical gear out of engagement with said horizontal gear and to maintain said wheel elevated above the plane of the surface on which the device is being used, said pin being depressible to interengage said gears and to bring said Wheel into contact with said surface.

2. The device set forth in claim 1, said dial having a zero position, and means for maintaining said dial in said zero position when said pin is undepressed.

3. The device set forth in claim 1, a second wheel rotatably mounted adjacent said first wheel and having graduations thereon, said second wheel having internal annular teeth, a pinion on said horizontal shaft normally positioned above and adapted to be lowered to engage said teeth upon depression of said pin.

4. The device set forth in claim 1, said dial having a zero position, means normally urging said dial into said zero position, and means for releasably maintaining said dial in said zero position.

JOHN H. SCOTT. 

